Fig. 1: The geometry of earthquake sources and stations used in this study.
From: Seismic evidence for a 1000 km mantle discontinuity under the Pacific
a The distribution of 600 earthquakes (circles color-coded for magnitude) and 8,642 seismic stations (triangles) used in this study, and b the corresponding source-receiver PP and SS midpoint distribution, shown as counts per 100 × 100 km2. Not all stations are simultaneously active for all earthquakes. The coverage, while global, is densest in the central Pacific area of interest. Note that we do not display the PS and SP bounce points, which provide additional illumination. In our images, the dominant contribution is from SS precursors.
